This invention relates to subsurface, i.e., underground, soil penetrating tools such as soil probes and soil augers, and particularly to such tools which offer special safety to the operator from electrical shorting. Detection probes and soil augers of various types have been devised heretofore for being manually forced down into the ground, e.g., to locate a conduit, a pipe, a storage tank, a septic tank or other buried objects, or to auger out soil samples and the like. To operate the tool, the operator grips a transverse handle on the upper end of a shaft having a pointed tip or an auger bit on its lower end, and advances the shaft down into the ground. When using such tools, one serious concern for the operator is the possibility of engaging a buried electrical conductor. The pointed tip or auger bit enables the tool to inadvertently penetrate the insulation of the electrical conductor, to potentially cause electrical shorting to the operator. This can cause injury or death to the operator and persons standing nearby.
In attempts to lessen this potential danger, some soil penetrating tools have an insulative jacket on the handle, as is true for the prior art probe in FIG. 7 herein. Other tools which have been marketed have a fiberglass reinforced polymeric shaft with an attached lower end pointed tip or auger bit for penetration of the ground. However, it has been discovered that if the polymeric shaft surface is nicked or scratched by the soil or rocks, moisture can penetrate and wick into the shaft interior to cause the tool to become unexpectedly electrically conductive. Another potential problem with reinforced polymeric shaft elements on probes and augers is that heavy stress, particularly if not oriented directly axially of the shaft, can cause the polymeric shaft to break. Hence, workmen may prefer to have the stronger steel shaft previously used rather than a plastic shaft. However, steel is electrically conductive, so that the safety of the operator is dependent on the layer of plastic insulation jacketing the handle.